1. Field of the Invention
This invention relates generally to an apparatus for electronically controlling the position of a work implement and more particularly to an apparatus for delivering a feedback signal indicative of the load applied to the work implement.
2. Description of the Prior Art
In the field of earthmoving, contractors typically own and operate a fleet of heavy equipment vehicles which constitute a large capital investment. The method of operation of these vehicles has a tremendous impact on the profitability of the business. For example, operation of the vehicles by an experienced and skilled workforce yields high productivity and efficiency and is favorably reflected in lower operating costs. Conversely, less skilled or new workers will invariably operate at a lower efficiency. Moreover, even skilled operators will experience periods of low productivity owing to outside factors such as fatigue, health, boredom, etc.
The lack of experience and skill are most evident in the larger vehicles where the ability to move tremendous amounts of earth is present. In such vehicles the operator is far removed from the actual work performed, having a limited view of the work implement and being insulated by the sheer mass of the vehicle from the force applied at the work implement. Engine rpm is also a good indicator of vehicle performance and can be easily monitored by engine sound; however, with the advent of better working conditions through enclosed air conditioned cabs, engine noise has become a much more subtle indicator. In these cases tachometers are useful in monitoring engine speed, but such visual indicators are impossible to constantly monitor as the operator's attention must be primarily focused on the work area. Further, while the operator's view of the work implement is limited, some information on efficiency can be visually gathered (i.e. the magnitude of side spill). Thus, the information obtained from the tachometer is at least partially offset by the loss of other visual information.
The present invention is directed to overcoming one or more of the problems as set forth above. In particular, it is desirable to provide an accurate indication of vehicle performance which is not distracting to the overall operation of the vehicle and is a substitute or aid to the subtle indications used by experienced and skilled operators.